The Applicant is aware of a process for extracting metal values from metal bearing ores which comprises, in a milling stage, milling wetted ore to produce a slurry; adding a lixiviant to the slurry from, the milling stage; passing the slurry to a leaching stage where the lixiviant leaches metal from the ores, with the metal thus being dissolved in the lixiviant; passing the leached slurry to a carbon-in-pulp (`CIP`) absorption section where the slurry is contacted with activated carbon particles which absorb the metal from the lixiviant; separating the carbon particles from the residual slurry; and, in a metal recovery section, recovering the metal from the carbon particles. Instead of the separate leaching and absorption stages, a combined leaching and carbon absorption (`CIL`) stage can be provided. The slurry conveyance to the various stages, as well as within each stage from one item of processing equipment to the next, is effected along pipelines, some of which are fitted with pumps. At least some of the pumps are centrifugal pumps each comprising a pump housing, and a rotatable pump shaft on which is mounted an impeller or the like, located in the housing and providing from the housing, with glands or seals being provided around the shaft where it passes through the housing. A gland service water arrangement, for flushing the glands with service water, is then also provided, with the gland service water after flushing the glands admixing with the slutty being pumped by the pump. Such a process is hereinafter also referred to as a `process of the kind described`.